Hindered hydroxyphenylalkanoates of substituted isopropanols

ABSTRACT

The compounds are esters having the formula ##EQU1## wherein R 1  is alkyl, cycloalkyl, alkylthioethyl or alkylpolyoxyalkylene, R 2  is the group ##SPC1## 
     R 3  is hydrogen, alkyl, cycloalkyl or α-methylbenzyl, R 4  is alkyl or cycloalkyl, R 5  is hydrogen or alkyl, provided when R 3  is hydrogen, R 5  is alkyl and R 4  is located on the carbon atom ortho to the hydroxyl group, A is a covalent carbon bond or lower alkylene, Q is the group ##SPC2## 
     R 6  and R 7  are independently hydrogen or alkyl, and Z is oxygen or sulfur. 
     The esters of this invention are prepared by usual esterification procedures from a substituted isopropanol and an acid or a derivative thereof, preferably the methyl ester. 
     The substituted isopropanols are prepared by the reaction of bis-glycidyl ethers of polyhydric phenols or of 1,3-diglycidyl derivatives of hydantoin with a mercaptide or alkoxide. 
     The compounds are useful as stabilizers for organic materials, especially polyolefins, which degrade upon exposure to light and heat.

DETAILED DISCLOSURE

This invention pertains to substituted isopropanol esters of hinderedhydroxyphenylalkanoic acids and to organic materials normally subject tooxidative, thermal and UV light degradation stabilized with said estercompounds.

More specifically the compounds of this invention are those having theformula ##EQU2## wherein R₁ is alkyl of 1 to 30 carbon atoms, cycloalkylof 5 to 12 carbon atoms, alkylthioethyl of 4 to 27 atoms in the chain oralkylpolyoxyalkylene of 4 to 27 atoms in the chain,

R₂ is the group ##SPC3##

R₃ is hydrogen, alkyl of 1 to 8 carbon atoms, cycloalkyl of 5 to 6carbon atoms or α-methylbenzyl,

R₄ is alkyl of 1 to 8 carbon atoms or cycloalkyl of 5 to 6 carbon atoms,

R₅ is hydrogen or lower alkyl of 1 to 4 carbon atoms, or R₃ and R₅together are a butylene chain which, together with the phenyl ring, forma tetrahydronaphthyl group, and provided when R₃ is hydrogen, R₅ isalkyl and R₄ is located on the carbon atom ortho to the hydroxyl group,

A is a covalent carbon bond or a straight or branched lower alkylenehaving 1 to 8 carbon atoms,

Q is the group ##SPC4##

R₆ is hydrogen or alkyl of 1 to 4 carbon atoms,

R₇ is hydrogen or alkyl of 1 to 8 carbon atoms,

R₈ is hydrogen, alkyl of 1 to 8 carbon atoms or aryl of 6 or 10 carbonatoms,

R₉ is hydrogen or alkyl of 1 to 4 carbon atoms, or R₈ and R₉ togetherform a lower alkylene chain of 4 to 7 carbon atoms,

T is alkylene of 1 to 12 carbon atoms, and

Z is oxygen or sulfur.

The R₁ group can be alkyl of 1 to 30 carbon atoms such as methyl,n-butyl, n-octyl, t-dodecyl, n-octadecyl, n-tetracosanyl orn-triacontanyl. Preferably R₁ is alkyl of 1 to 18 carbon atoms, such asmethyl, n-butyl, n-dodecyl or n-octadecyl. Most preferably for use instabilizing polyolefins such as polypropylene, polyethylene and olefincopolymer R₁ is alkyl of 8 to 18 carbon atoms.

The R₁ group can be cycloalkyl of 5 to 12 carbon atoms such ascyclopentyl, cyclohexyl, cyclooctyl or cyclododecyl.

R₁ is also alkylthioethyl of 4 to 27 atoms in the chain such as2-methylthioethyl, 2-(n-octylthio)ethyl and 2-tetracosanylthio)ethyl.

R₁ can also be alkylpolyoxyalkylene of 4 to 27 atoms in the chain havingthe general structure R°(OC_(n) H_(2n))_(h) or R°(OCH₂ CHR')_(h) whereR° is alkyl of 1 to 18 carbon atoms, n is 2 to 4, R' is hydrogen, methylor ethyl and h is 1 to 3.

The R₃ and R₄ groups can be straight or branched lower alkyl groups,having 1 to 8 carbon atoms as for example, methyl, ethyl, isopropyl,n-butyl, tert-butyl, tert-amyl or n-octyl. R₃ and R₄ can also becycloalkyl of 5 to 6 carbon atoms such as cyclopentyl or cyclohexyl. R₃can also be α-methylbenzyl.

Preferably R₃ is a straight or branched alkyl group of 1 to 4 carbonatoms, such as methyl, ethyl, isopropyl or tert-butyl. Most preferablyR₃ is methyl or tert-butyl.

Preferably R₄ is a branched alkyl of 3 to 8 carbon atoms, such asisopropyl, sec-butyl, tert-butyl, sec-amyl, tert-amyl, sec-octyl ortert-octyl. Most preferably R₄ is tert-butyl.

Preferably R₅ is hydrogen or alkyl of 1 to 3 carbon atoms, such asmethyl, ethyl or n-propyl. Most preferably R₅ is hydrogen or methyl.

A is a covalent carbon bond or a straight or branched lower alkylene of1 to 8 carbon atoms such as methylene, ethylene, 2,3-propylene,trimethylene, 1,1-dimethylethylene, 1,1-butylidene,2-methyl-1,1-propylidene or 1,1-octylidene. Preferably A is a straightchain alkylene of 1 to 3 carbon atoms, that is, methylene, ethylene ortrimethylene. Most preferably A is methylene or ethylene.

R₆ is hydrogen or alkyl of 1 to 4 carbon atoms such as methyl, ethyl orn-butyl. Preferably R₆ is hydrogen or methyl. Most preferably R₆ ismethyl.

R₇ is hydrogen or alkyl of 1 to 8 carbon atoms such as methyl, ethyl,n-butyl or n-octyl. Preferably R₇ is hydrogen or alkyl of 1 to 3 carbonatoms such as methyl, ethyl or n-propyl. Most preferably R₇ is methyl.

R₈ is hydrogen, alkyl of 1 to 8 carbon atoms such as methyl, ethyl,n-propyl, isopropyl, sec-butyl, n-amyl or n-octyl. Preferably R₈ ishydrogen or alkyl of 1 to 4 carbon atoms such as methyl, ethyl,isopropyl or n-butyl. Most preferably R₈ is alkyl of 1 to 4 carbonatoms.

R₈ is also aryl of 6 or 10 carbon atoms such as phenyl or α-naphthyl.

R₉ is hydrogen or lower alkyl of 1 to 4 carbon atoms such as methyl,ethyl or n-butyl. Preferably R₉ is hydrogen or methyl. Most preferablyR₉ is methyl.

R₈ and R₉ together form a lower alkylene chain of 4 to 7 carbon atomsand with the carbon atom to which both are attached form a cycloalkaneattached to the hydantoin ring at a common spiro carbon. Preferably R₈and R₉ together form a pentamethylene group.

T is alkylene of 1 to 12 carbon atoms such as methylene, ethylene,1,4-butylene, hexamethylene or dodecamethylene.

The esters of this invention are prepared by usual esterificationprocedures from the appropriate substituted 2-propanol and an acid ofthe formula I ##SPC5##

an acid halide or acid anhydride thereof or from the corresponing loweralkyl, preferably methyl, ester.

The acid halide derivatives of the above cited acids are made in aconventional manner using standard halogenating agents such as thionylchloride, phosphorus trichloride and phosphorus oxychloride.

The lower alkyl esters, usually methyl, are conveniently made by an acidcatalyzed reaction of the above-cited acid with a lower alcohol, such asmethanol.

Where A is ethylene or substituted ethylene, the lower alkyl esters areconveniently made by reaction of a substituted phenol (II) with anacrylate ester as represented below. ##SPC6##

where R₁₀ is hydrogen or lower alkyl of 1 to 6 carbon atoms and R isalkyl of 1 to 4 carbon atoms. Processes of this type are disclosed forexample in U.S. Pat. No. 3,247,240 (Apr. 9, 1966) and U.S. Pat. No.3,364,250 (Jan. 16, 1968).

The above-described ester intermediates may also be made by reacting asubstituted phenol with an acrylonitrile as represented below. ##SPC7##

This reaction is analogous to that disclosed in U.S. Pat. No. 3,121,732(Feb. 18, 1964).

The acids where A is methylene are conveniently made by the sequencebelow ##SPC8##

where M is an alkali metal such as sodium or potassium and R₁₁ and R₁₂are lower alkyl of 1 to 8 carbon atoms or together form a morpholine orpiperidine ring with the nitrogen atom. Preferably R₁₁ and R₁₂ aremethyl.

Substitution of higher aldehydes such as n-butanal or n-octanal forformaldehyde in the reactions outlined in the previous paragraph leadsto the preparation of acids of formula (I) where A is 1,1-alkylidene.

Acids of formula I can also be prepared by reaction of substitutedphenolate anions with appropriate halogenoalkane carboxylate esters,amides or nitriles where A may be straight or branched alkylene of 2 to8 carbon atoms.

Most of the di- and trialkylated phenols (II) contemplated for use asstarting materials to make the compounds of this invention are knowncompounds which are available commercially. The preparation of2,6-diisopropyl-3-methylphenol and 2,6-di-tert-butyl-3-methylphenol isdisclosed in Japanese patent application 7015,491. The preparation of2,3-dimethyl-6-tert-butylphenol is disclosed by G. Parc, Revue deL'Institut Francais du Petrole, XV, 693 (1960). Other substitutedphenols may be made by the selected alkylation of phenolic startingmaterials using acid catalysis such as p-toluene sulfonic acid andselected olefins such as propylene, isobutylene and2,4,4-trimethylpentene-1.

Although R₄ may be either ortho to the hydroxyl group or the A group,preferably R₄ is ortho to the hydroxyl in esters of this invention.

The substituted isopropanol intermediates are reacted with the hinderedphenolalkanoic acid derivatives described previously to prepare theesters of this invention in the presence of a suitable basic catalystsuch as sodium methoxide, lithium amide or lithium hydride. ##SPC9##

The key substituted isopropanol intermediates required to prepare theesters of this invention are conveniently made from glycidyl ethers ofpolyhydric phenols or from N-glycidyl derivatives of hydantoins.##EQU3##

    1.    R.sub.1 Z.sup.-M.sup.+.sup.(solvent optional)

    2.    H.sup.+X.sup.- ##EQU4## where R.sub.1 and Z are defined as before, M.sup.+ is a cation such as lithium, sodium or potassium and X.sup.- is an anion such as chloride or bromide.

These substituted 2-propanols are useful as chemical intermediates inthe preparation of stabilizers of this invention and a myriad of otherproducts such as synergists, extreme pressure additives for lubricants,pesticides, fuel additives and the like.

Esters of 3,5-dialkyl-4-hydroxyphenylalkanoic acids and alkane polyolsare described in U.S. Pat. No. 3,644,482. Many of these compounds arecrystalline or vitreous solids which are highly effective stabilizersagainst thermo-oxidative aging, ie they are solid antioxidants. Moreoverthey generally have only limited solubility in those solvents employedtechnically in large amounts such as aliphatic hydrocarbons.

These properties are highly advantageous in many applications, butrepresent disadvantages in others. It is thus difficult to utilize thesesolid compounds in technical processes in which the additives arepumped, proportioned and fed in fluid form, for example in hydrocarbonsolution polymerization processes.

Somewhat related, sulfur-containing esters of3,5-dialkyl-4-hydroxyphenylalkanoic acid are described in U.S. Pat. Nos.3,285,855 and 3,441,575. These are the 2-alkylthioethyl esters, somebeing liquids and others solids.

Esters of 3,5-dialkyl-4-hydroxyphenylalkanoic acids and mixtures of atleast two non-identical alkanediols are described in U.S. Pat. No.3,779,945. These mixed esters do provide very suitable stabilization fororganic materials subject to degradation, and in addition are liquidswhich can be pumped, proportioned and fed and which are quite soluble inorganic solvents permitting their use in highly concentrated solutions.

The esters of this invention are also liquids which exhibit all theprocessing, solubility and utility advantages shown by the mixed estersdescribed in U.S. Pat. No. 3,779,945.

The substrates of particular importance are olefin polymers such aspolyethylene, polypropylene, olefin copolymers and blends thereof.Polypropylene is especially well stabilized with the compounds of thisinvention.

The stabilizers of this invention are particularly useful in protectingpolymer compositions subjected to high temperature processing as well asend uses involving elevated temperatures.

The esters of this invention exhibit good stabilization activity inpolypropylene is the absence of a thio ester costabilizer such asdistearyl β-thiodipropionate (DSTDP), but with the addition of DSTDPco-stabilizer, the stabilization protection afforded polypropyleneincreases greatly in some cases far exceeding that provided in similarformulations by commercial stabilizers described in U.S. Pat. No.3,285,855 or by liquid mixed ester stabilizers described in U.S. Pat.No. 3,779,945.

The high degree or protection afforded polypropylene by the esters ofthis invention occurs at a low molar concentration of the activehindered phenol moiety compared to that of many commercial stabilizers.In addition, the less additive required in a polymer composition usuallybenefits retention of its basic physical properties.

It is understood that the scope of the invention is not limited by thefollowing postulations nor that the stabilization effectiveness of theesters of this invention necessarily results from the proposedexplanations thereof or or by the schematic representations presented.Although the reason for this particularly effective stabilizationactivity of the esters of this invention is unknown, it is theorizedthat the molecular structure of these esters must in some way permit amore efficacious utilization of the hindred phenol part of the moleculesin the polypropylene system allowing less of the hindered phenol toperform the necessary stabilization function.

While the liquid physical nature of these esters may well facilitatetheir introduction and compatibilization in the amorphous areas of thepolypropylene system where stabilization activity is most needed, it ispostulated that the molecular structure of the esters is significantlydifferent from the prior art stabilizers and that this difference instructure may well account for the great effectiveness of the esters ofthis invention.

These esters are all derived from substituted isopropanols having a longalkylthio or alkoxy solubilizing hydrocarbon substituent on the 3-carbonatoms and being coupled on the 1-carbon atoms with an oxyaryleneoxy oran N,N'-heterocyclic moiety. This forms a rather rigid internalmolecular structure having good solubility properties having attachedjust on each end an active hindered phenol moiety and on the extremeoutside of molecule in each direction a long solubilizing hydrocarbonmoiety. This comination of molecular structure with concomitantsolubility and physical properties affords good stabilization topolypropylene systems.

The prior art stabilizers are of four general types all differingsignificantly from the instant esters. In Type 1 a plurality of hinderedphenol moieties surround a small hydrocarbon linking group. Thesematerials are generally solids and relatively high melting materialswith concomitant limited solubility in aliphatic hydrocarbon solvents.See U.S. Pat. No. 3,644,482.

In Type 2, the hindered phenol moiety is joined by a single longhydrocarbon chain sometimes containing a heteroatom such as sulfur. The2-(n-alkylthio)ethyl esters related to the esters of this invention fallin this class. (See U.S. Pat. Nos. 3,330,859 and 3,441,575.)

In Type 3, two hindered phenol moieties are attached to an alkylenechain sometimes containing a heteroatom such as sulfur. (See U.S. Pat.No. 3,644,482).

In Type 4, mixed esters derived from a hindered phenolalkanoic acid anda mixture of alkyl substituted alkanediols result in liquid stabilizershaving two hindered phenol moieties attached to an alkylene chainsubstituted with pendant lower alkyl groups (See U.S. Pat. No.3,779,945).

A comparison of the test data on the best ester compounds of Types 1-4described above and given in U.S. Pat. Nos. 3,285,855, 3,758,549 and3,779,945 with test data on the esters of the present invention is givenin Example 8, Table I. The esters of this invention at only 40% theconcentration of the best prior art esters exhibit equal or betterstabilization effectiveness in polypropylene.

Schematically these types of stabilizers may be represented below where⁺ represents a hindered phenolic moiety, and -- a short linking chain orpendant group and a long solubilizing hydrocarbon chain which mayinclude a hereroatom such as oxygen or sulfur therein.

A comparison of these schematic models clearly indicates that the estersof the present invention are structurally and configurationallydifferent and are not anticipated or suggested by the prior artcompounds. ##SPC10##

Esters of this invention ##SPC11##

The ester compounds of the present invention provide excellentstabilization protection not only for polymeric substrates such aspolyolefins, polyacetals, polyesters and polyamides, but also fornon-polymeric substances such as oils which undergo thermal and actinicdegradation.

For many purposes, it is convenient or even necessary that thestabilizer additive be a solid, preferably white, somewhat high meltingmaterial. This is especially true for polymeric substrates where smallamounts of the additive are to be isolated then weighed accurately andadded discretely into the polymeric system to be stabilized.

The compounds of the instant invention provide an equally beneficialphysical form for such stabilizers are essentially colorless, highboiling liquids. These materials are stable, possess the requisitestructures for enhancing solubility and compatibility in the substratesto be stabilized and provide by their totally liquid nature, ascontrasted to a high-melting solid or a low-melting semi-solid, aparticularly convenient method of addition to the substrate systems. Thecompounds of this invention can be accurately metered and monitored intothe substrate systems to be stabilized using standard liquid pumpingdevices.

The esters of the invention are expected to find particular utility instabilizing liquid substrates such as oils and in stabilizing polymericsubstrates where liquid pumping devices can be expeditiously employed inadding the stabilizers during polymer processing.

The hindered hydroxyphenyl alkanoates of this invention are stabilizersof organic material normally subject to thermal and oxidativedeterioration. Materials which are thus stabilized include syntheticorganic polymeric substances such as poly-α-olefins, polyethylene,polypropylene, crosslinked polyethylene, polybutylene includingcopolymers of α-olefins such as ethylene/propylene copolymer; dienessuch as polybutadiene, polyisoprene, and the like, including copolymerswith other monomers; polyurethanes and polyamides such aspolyhexamethylene adipamide and polycaprolactam; polyesters such aspolyethylene terephthalates; polycarbonates; polyacetals; unsaturatedpolyesters; polystyrene, polyethylene oxide; and copolymers such asthose of high impact polystyrene containing copolymers of butadiene andstyrene and those formed by the copolymerization of acrylonitrile,butadiene and/or styrene, ABS;SAN; natural and synthetic rubbers such asethylene/propylene/diene copolymer (EPDM) and chlorinated rubber;polyphenylene oxide and copolymers; vinyl resins formed from thepolymerization of vinyl halides or from the co-polymerization of vinylhalides with unsaturated polymerizable of vinyl halides with unsaturatedpolymerizable compounds, e.g., vinyl esters, α,β-unsaturated ketones,α,β-unsaturated aldehydes and unsaturated hydrocarbons such asbutadienes and styrene; and plasticized polyvinyl chloride.

Other materials which can be stabilized by the compounds of the presentinvention include lubricating oil of the aliphatic ester type, i.e.,di(2-ethylene) azelate and other synthetic ester lubricants,pentaerythritol tetracaproate, and the like; spinning lubricants of thepolyester type; animal and vegetable derived oils, e.g., linseed oil,fat, tallow, lard, peanut oil, cod liver oil, castor oil, palm oil, cornoil, cottonseed oil, and the like; hydrocarbon materials such asgasoline, mineral oil, fuel oil, drying oil, mineral lube oils, cuttingfluids, waxes, resins and the like, salts of fatty acids such as soapsand the like; and alkylene glycols, e.g., β-methoxyethylene glycol,methoxytriethylene glycol, triethylene glycol, octaethylene glycol,dibutylene glycol, dipropylene glycol and the like.

The substrates of particular importance are olefin polymers such aspolyethylene, polypropylene, polybutylene and ethylene/vinyl acetate.Polypropylene is especially well stabilized with the compounds of thisinvention.

In general, the stabilizers of this invention are employed from about0.01 to about 5% by weight of the stabilized composition, although thiswill vary with the particular substrate and application. An advantageousrange is from about 0.05 to about 2% and especially from about 0.1 toabout 1%.

For addition to polymeric substrates, the stabilizers can be blendedbefore polymerization or after polymerization, during the usualprocessing operations, for example, by dry blending, extrudercompounding and hot-milling. The composition then can be extruded,pressed, injected molded or otherwise fabricated into films, fibers,filaments, molded items and the like. The heat stabilizing properties ofthese compounds advantageously stabilize the polymer against degradationduring such processing at the high temperature generally encountered.However, the useful life of polymeric materials is also extended bythese stabilizers far beyond their ability to survive processing.

The stabilizers can also be dissolved in suitable solvents and sprayedon the surface of films, fabrics, filaments or the like to provideeffective stabilization.

These compounds can also be used in combination with other additivessuch as sulfur-containing esters, e.g., distearyl β-thiodipropionate(DSTDP) in an amount of from 0.01 to 2% by weight of the organicmaterial, and the like, pourpoint depressants, corrosion and rustinhibitors, dispersing agents, emulsifiers, antifoaming agents, carbonblack, accelerators and other chemicals used in rubber compounding,plasticizers, color stabilizers, antistatic agents, antislip agents,antiblock agents, surface active agents, fillers, organophosphites,organothiophosphites, heat stabilizers, ultraviolet light stabiilizers,antiozonants, dyes, pigments, metal deactivators, metal chelatingagents, dyesites and the like. Often combinations such as these,particularly the sulfur containing esters, the phosphites and/or theultraviolet light stabilizers will produce superior results in certainapplications to those expected by the properties of the individualcomponents.

The following formula represents co-stabilizers which are in certaininstances very useful in combination with the stabilizers of thisinvention: ##EQU5## wherein R is an alkyl group having from 6 to 24carbon atoms; and n is an integer from 1 to 6. Especially usefulcompounds of this type are dilauryl β-thiodipropionate and distearylβ-thiodipropionate. The above co-stabilizers are used in the amount offrom 0.01 to 2% by weight of the organic material, and preferably from0.1 to 1%.

In addition to the above noted additives that can be employed incombination with the compounds of this invention, it is often especiallyadvantageous to employ also light stabilizers. The light stabilizers areused in the amount of from 0.01 to 5% by weight of the organic material,and preferably from 0.1 to 1%. Illustrative examples of lightstabilizers are listed below.

UV-Absorbers and light protection agents

2-(2'-hydroxyphenyl)-2H-benztriazoles, such as, for example, the5'-methyl-, 3',5'-di-tert.-butyl-, 5'-tert.-butyl-,5'-(1,1,3,3-tetramethylbutyl)-, 5-chloro -3', 5'-di-tert.-butyl-,5-chloro-3'-tert.-butyl5'-methyl-, 3'-sec.-butyl-5'-tert.-butyl-,3'-{α-methylbenzyl}-5'methyl-, 3'-{α-methylbenzyl}-5'-methyl-5-chloro-,4'-hydroxy-, 4'-methoxy-, 4'-octoxy-, 3',5'-di-tert.-amyl-,3'-methyl-5'-carbomethoxyethyl5-chloro-3',5'-di-tert.-amyl-or4'-tert-octyl- derivatives.

2,4-bis-(2'-hydroxyphenyl)-6-alkyl-s-triazines, such as, for example,the 6-ethyl-, 6-undecyl- or 6-heptadecyl- derivatives.

2-hydroxybenzophenones, such as, for example, the 4-hydroxy-,4-methoxy-, 4-octoxy-, 4-decyloxy, 4-dodecyloxy-, 4-benzyloxy-,4,2',4'-trihydroxy- or 2'-hydroxy-4,4'-dimethoxy- derivatives.

1,3-bis-(2'-hydroxybenzoyl)benzenes, such as, for example,1,3-bis-(2'-hydroxy-4'-hexyloxybenzoyl)benzene,1,3-bis-(2'hydroxy-4'-octoxybenzoyl)benzene and1,3-bis-(2'-hydroxy-4'-dodecyloxybenzoyl)benzene.

Esters of optionally substituted benzoic acids, such as, for example,phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol,bis-(4-tert.-butylbenzoyl)resorcinol, benzoylresorcinol,3,5-di-tert.-butyl-4-hydroxybenzoic acid 2,4-di-tert.-butylphenyl ester,octadecyl ester or 2-methyl-4,6-di-tert.-butylphenyl ester, and thealkyl esters of4-(3,5-di-tert-butyl-4-hydroxybenzoyloxy)-3,5-di-tert-butylbenzoic acid.

Acrylates, such as, for example, α-cyano-β,β-diphenylacrylic acid ethylester or isooctyl ester, α-carbomethoxycinnamic acid methyl ester,α-cyano-β-methyl-p-methoxycinnamic acid methyl ester or butyl ester andN-(β-carbomethoxy-vinyl)-2-methylindoline.

Nickel compounds, such as, for example, nickel complexes of2,2'-thio-bis-4-(1,1,3,3-tetramethylbutyl)-phenol, such as the 1:1 and1:2 complex, optionally with other ligands such as n-butyl-,triethanol-, cyclohexyl- or N-cyclohexyldiethanolamine; nickel complexesof bis-{2-hydroxy-4-(1,1,3,3-tetramethylbutyl)phenyl}sulfone, such asthe 2:1 complex, optionally with other ligands such as 2-ethylcaproicacid; nickel dibutyldithiocarbamate, nickel salts of4-hydroxy-3,5-di-tert.-butylbenzylphosphonic acid monoalkyl esters, suchas the methyl, ethyl or butyl ester, the nickel complex of(2-hydroxy-4-methylphenyl)undecylketonoxime and nickel3,5-di-tert.-butyl-4-hydroxybenzoate.

Oxalic acid diamides, such as, for example, 4,4'-dioctyloxyoxanilide,2,2'-dioctyloxy-5,5'-di-tert.-butyloxanilide,2,2'-didodecyloxy-5,5'-di-tert-butyloxanilide,2-ethoxy-5-tert-butyl-2'-ethyloxanilide, 2-ethoxy-2'-ethyloxanilide,N,N'-bis-(3-dimethylaminopropyl)oxalamide, mixtures of o- and p-methoxyand o- and p-ethoxy-di-substituted oxanilides and mixtures of2-ethoxy-5-tert.-butyl2'-ethyloxanilide with2-ethoxy-2'-ethyl-5,4'-di-tert.-butyloxanilide.

Sterically hindered amines, such as, for example4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy2,2,6,6-tetramethylpiperidine, bis-(2,2,6,6-tetramethylpiperidyl)sebacate and 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decan-2,4-dione.

For exemplification purposes only listed below are compounds of thisinvention which are useful as stabilizers as discussed above.

2,2-bis[4-(3-methylthio-2-(3,5-di-tert-octyl-4-hydroxyhydrocinnamoyloxy))propoxyphenyl]propane

2,2-bis[4-(3-n-dodecyloxy-2-(3,5-di-tert-butyl-4-hydroxyphenylacetoxy))propoxyphenyl]butane

2,2-bis[4-(3-cyclohexylthio-2-(4-(3-methyl-5-tertbutyl-4-hydroxyphenyl)butyroxy))propoxyphenyl]butane

1,3-bis[3-(2-n-octadecylthio)ethyl-2-(3,5-di-tertamyl-4-hydroxyhydrocinnamoyloxy)-propyl]-5,5-dimethylhydantoin

2,2-bis[4-(3-n-octyloxy-2-(2,3-dimethyl-5-tert-butyl-4-hydroxyphenylacetoxy))propoxyphenyl]propane

1,3-bis[3-n-dodecylthio-2-(2-methyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy)propyl]-5,5-dimethylhydantoin

The following examples are illustrative of the invention, but are notmeant to limit the scope of the same in any fashion. The temperaturesare given in degrees centigrade unless otherwise noted.

EXAMPLE 12,2-Bis-[4-(3-n-dodecylthio-2-(3-methyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy))-propoxyphenyl]propane

a. A mixture of 37.3 grams (0.05 mole) of2,2-bis-[4-(3-n-dodecylthio-2-hydroxy)propoxyphenyl]propane and 0.08grams (0.01 mole) of lithium hydride was placed under a nitrogenatmosphere and heated to about 90°C with stirring. To this mixture wasadded 27.5 grams (0.11 mole) of methyl3-methyl-5-tert-butyl-4-hydroxyhydrocinnamate. The resulting reactionmixture was stirred and heated at 125°-160°C for 3.5 hours atatmospheric pressure and then for an additional 5 hours at 140°-160°C at1±0.3 mm pressure. The mixture was then cooled and acidified with 1.2grams (0.02 mole) of glacial acetic acid. The crude product wasdissolved in 100 ml of a 50:50 benzene: heptane mixture, treated with 3grams of Hi-Flo Filtercel and clarified by filtration. The filtrate waspercolated through a bed of 1070 grams of alumina (Woelm neutral,activity II). Elution was started with 50:50 benzene: heptane andconcluded with 50:50 benzene: chloroform. The pure product fractionswere combined, stripped of solvent and dried to constant weight at 80°Cand 0.1 mm. The above-named ester was obtained as a viscous syrup.(Compound 1)

Calcd for C₇₃ H₁₁₂ O₈ S₂ : C,74.19; H,9.55; S,5.42. Found: C,74.15;H,9.43; S,5.06.

b. 2,2-bis[4-(3-n-dodecylthio-2-hydroxy)-propoxyphenyl]propane

To a solution of 13.7 grams (0.21 mole) of potassium hydroxide in 50 mlwater was added 40.5 grams (0.20 mole) of n-dodecyl mercaptan and themixture stirred for 15 minutes. To this new solution was added asolution of 34.0 grams (0.10 mole) of2,2-bis[4-(2,3-epoxy)propoxyphenyl]-propane in 75 ml of warm ethanol.The resulting mixture was stirred for 16 hours at 50°C. The reactionmixture was then cooled and neutralized with 17.5 ml (0.21 mole) ofconcentrated hydrochloric acid yielding an oily product. 200 ml of waterwas added and the product extracted into ether using one 200 ml and two100 ml portions. The combined ether extracts were washed with saturatedsodium chloride solution and dried over molecule sieves (Linde 4A).After filtration and removal of the ether under vacuum, the desiredproduct was isolated in quantitative yield (67.7 grams).

Calcd for C₄₅ H₇₆ O₄ S: C,72.52; H,10.27; S,8.60. Found: C,72.67;H,10.00; S,8.48.

EXAMPLE 22,2-Bis-[4-(3-n-dodecylthio-2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))propoxyphenyl]propane

When in Example 1, an equivalent amount of methyl3,5-di-tert-butyl-4-hydroxyhydrocinnamate is substituted for methyl3-methyl-5-tert-butyl-4-hydroxyhydrocinnamate, the above-named ester isobtained as a viscous syrup.

EXAMPLE 32,2-Bis-[4-(3-n-octadecylthio-2-(3-methyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy))-propoxyphenyl]propane

When in Example 1, an equivalent amount of2,2-bis-[4-(3-n-octadecylthio-2-hydroxy)-propoxyphenyl]propane issubstituted for2,2-bis-[4-(3-n-dodecylthio-2-hydroxy)-propoxyphenyl]propane, theabove-named ester is obtained as a viscous syrup.

EXAMPLE 42,2-Bis-[4-(3-methoxy-2-(3-methyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy))propoxyphenyl]propane

When in Example 1, an equivalent amount of2,2-bis-[4-(3-methoxy-2-hydroxy)propoxyphenyl]propane is substituted for2,2-bis-[4-(3-n-dodecylthio-2-hydroxy)propoxyphenyl]propane, theabove-named ester is obtained as a viscous syrup.

EXAMPLE 52,2-Bis-[4-(3-n-dodecylthio-2-(2,3-dimethyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy))-propoxyphenyl]propane

When in Example 1, an equivalent amount of methyl2,3-dimethyl-5-tert-butyl-4-hydroxyhydrocinnamate is substituted formethyl 3-methyl-5-tert-butyl-4-hydroxyhydrocinnamate, the above-namedester is obtained as a viscous liquid.

EXAMPLE 61,3-Bis[3-n-dodecylthio-2-(3-methyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy)propyl]-5,5-dimethylhydantoin

When in Example 1, an equivalent amount of1,3-bis(3-n-dodecylthio-2-hydroxypropyl)-5,5-dimethylhydantoin issubstituted for2,2-bis[4-(3-n-dodecylthio-2-hydroxy)-propoxyphenyl]propane, the abovenamed ester is obtained.

EXAMPLE 71,3-Bis[3-n-octadecylthio-2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)propyl]-5-ethyl-5-methylhydantoin

When in Example 2, an equivalent amount of1,3-bis(3-n-octadecylthio-2-hydroxypropyl)-5-ethyl-5-methylhydantoin issubstituted for2,2-bis[4-(3-n-dodecylthio-2-hydroxy)propoxyphenyl]propane, theabove-named ester is obtained.

EXAMPLE 8

Unstabilized polypropylene powder (Hercules Profax 6501) was thoroughlyblended with 0.2% by weight of the indicated stabilizer compound. Alsoprepared were samples of polypropylene containing 0.1% by weight of thesame stabilizer and 0.3% by weight of distearyl β-thiodipropionate(DSTDP). The blended materials were then milled on a two-roll mill at182°C for 10 minutes after which time the stabilized polypropylene wassheeted from the mill and allowed to cool.

The milled polypropylene sheets were then cut into pieces and pressedfor 7 minutes on a hydraulic press at 218°C and 275 psi (19.25 Kg/cm²)pressure. The resulting plaques of 25 mil (0.635 mm) thickness weretested for resistance to accelerated aging in a forced draft oven at150°C. When the plaques showed the first signs of decomposition (e.g.cracking or brown edges) they were considered to have failed. Theresults are shown in Table I below.

                  Table I                                                         ______________________________________                                        Oven Aging of Polypropylene Plaques                                           Percent Stabilizer      Hours to Failure                                      ______________________________________                                        Unstabilized Polypropylene                                                                            3                                                     0.3% DSTDT only         100                                                   0.2% Compound 1         690                                                   0.1% Compound 1 + 0.3% DSTDP                                                                          1420                                                  0.5% 2-(n-octadecylthio)ethyl                                                 3.5-di-tert-butyl-4-hydroxy-                                                  phenylacetate           1000                                                  (Example 1, US 3,285,855)                                                     0.5% 2-(n-octadecylthio)ethyl                                                 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-                                        propionate              1220                                                  (Example 2, US 3,285,855)                                                     0.5% 2-(n-octadecylthio)ethyl 3,5-di                                          tert-butyl-4-hydroxybenzoate                                                                          740                                                   (Example 3, US 3,285,855)                                                     0.5% β-thiodiethylene bis-(3,5-di-tert-                                  butyl-4-hydroxyphenylacetate)                                                                         460                                                   0.5% β-thiodiethylene bis-[3-(3,5-di-                                    tert-butyl-4-hydroxyphenyl)-                                                                          1350                                                  propionate]                                                                   0.5% oxydiethylene bis-[3-(3,5-di-                                            tert-butyl-4-hydroxyphenyl)propionate]                                                                1000                                                  0.5% n-octadecyl 3-(3,5-di-tert-butyl-4-                                      hydroxyphenyl)propionate                                                                              630                                                   (Example 4, US 3,285,855)                                                     0.5% pentaerythritol tetrakis[3-(3,5-                                         di-tert-butyl-4-hydroxyphenyl)-                                                                       1470                                                  propionate]                                                                   (Example 6, US 3,285,855)                                                     0.3% same stabilizer    1170                                                  (Example 5, US 3,758,549)                                                     0.1% same stabilizer + 0.5% dilauryl                                          β-thiodipropionate 975                                                   (Example 6, US 3,285,855)                                                     0.5% 1,2-propylene bis[3-(3,5-di-tert-                                        butyl-4-hydroxyphenyl)propionate]                                                                     780                                                   (Example 7, US 3,285,855)                                                     0.5% ethylene bis(3,5-di-tert-butyl-                                          4-hydroxyphenylacetate) 475                                                   0.5% ethylene bis[3-(3,5-di-tert-butyl-                                       4-hydroxyphenyl)propionate]                                                                           820                                                   0.5% 2,2-dimethylpropylene bis[3-                                             (3,5-di-tert-butyl-4-hydroxyphenyl)-                                          propionate]             510                                                   0.5% 1,1,1-butanetriyl tris[3-                                                (3,5-di-tert-butyl-4-hydroxyphenyl)-                                          propionate]             1750                                                  0.2% 2,4,4-trimethylhexylene (70%) +                                                                  936                                                   2,2,4-trimethylhexylene (30%)                                                 bis[3-(3,5-di-tert-butyl-4-                                                   hydroxyphenyl)propionate]                                                     (Example 5, US 3,779,945)                                                     [40 mil(1 mm) thick films tested]                                             0.1% above mixed ester stabilizer                                                                     1080                                                  + 0.3% dilauryl β-thiodipropionate                                       [40 mil (1 mm) thick films tested]                                            ______________________________________                                    

The esters of this invention are particularly active in the presence ofa thio ester co-stabilizer.

The esters of this invention of 0.2% concentration are in some casesmore effective than the 2-(n-octadecylthio)-ethyl esters described inU.S. Pat. Nos. 3,285,855 and 3,441,575 tested at the 0.5% concentrationin polypropylene. Thus the esters of this invention at 40% of theconcentration of the most closely related prior art stabilizers exhibitcomparable performance as seen in Example 8.

In comparison with the liquid mixed esters (Example 5, U.S. Pat. No.3,779,945) thinner films (25 mil vs 40 mil) were used with the esters ofthis invention which still exhibited far superior performance in thepresence of a thio ester co-stabilizer in the thinner films than did theliquid mixed esters in a comparable formulation tested in thicker filmswhich would normally be expected to be more stable.

EXAMPLE 9

Test specimens were prepared exactly as described in Example 8 exceptthat the stabilized polypropylene contained 0.2% by weight of thevarious esters of this invention and 0.5% by weight of2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chloro-2H-benzotriazole as aco-stabilizer. Results of accelerated aging tests in a forced draft ovenat 150°C are shown in Table II below

                  Table II                                                        ______________________________________                                        Compound Number      Oven Aging at 150°C                               (plus co-stabilizer) Hours to Failure                                         ______________________________________                                        Unstabilized Polypropylene                                                                            3                                                       1                    680                                                    ______________________________________                                    

EXAMPLE 10

Pellets (500 g) of unstabilized nylon-6,6 (Zytel 101, DuPont) are placedin a Kitchen Aid Mixer. With mixing a solution of 0.5% (based on theweight of nylon) of2,2-bis[4-(3-n-octadecylthio-2-(2,3-diethyl-5-tert-butyl4-hydroxyhydrocinnamoyloxy))-propoxyphenyl]propanein 20 ml of methylene chloride is added slowly. Sodium hypophosphite(0.5 gm 0.14) is dissolved in 20 ml of water and added slowly withmixing to the nylon pellets after the antioxidant solution has beenadded and most of the methylene chloride has evaporated. The stabilizedpellets are dried at 80°C at <<1 mm Hg. for 4 hours.

The polyamide formulation is extruded at 600°F (315.6°C) through atone-fourth inch (0.635 cm) die into a rod which is water cooled andchopped into pellets. A three-fourth inch (1.905 cm) Brabender extruder,equipped with a nylon screw, is used. The pellets are dried at 80°C at<1 mm for 4 hours.

The dried pellets are compression molded into 5 mil (0.127 mm) thickfilm by pressing at 290°C for 4 minutes at 6000 psi (57.75 Kg/cm²). Thefilms are oven aged at 150°C in a forced draft oven and samples areremoved periodically. The specific viscosity of the samples aredetermined using a 1% formic acid solution at 25°C. The samplestabilized with the above noted stabilizer required longer aging time toreduce its viscosity by one-half than the unstabilized sample.

EXAMPLE 11

Unstabilized high impact polystyrene resin is dry blended with 0.01% byweight of the resin of2,2-bis[4-(3-n-hexadecylthio-2-(2,3-dimethyl-5-tert-butyl4-hydroxyphenylacetoxy))propoxyphenyl]propane.The resin is then extrusion compounded on a 1 inch (2.54 cm) 24/1=L/Dextruder, melt temperature 500°F (260°C) and pressed for 7 minutes at atemperature of 163°C and a pressure of 2000 psi (140 Kg/cm²) into asheet of uniform thickness of 100 mil (2.54 mm). The sheets are then cutinto plaques of 2 inch × 2 inch (5.08 cm × 5.08 cm.). The plaques arethen oven aged at 80°C and color measurements made periodically using aHunter Color Difference Meter Model D25. The polystyrene samplesstabilized with the above stabilizer develops the undesirable yellowdisoloration substantially later than the time that such discolorationoccurred in the unstabilized samples.

EXAMPLE 12

Unstabilized linear polyethylene (HiFax 4401) is solvent blended inmethylene chloride with 0.2 by weight of the substrate of 1,3-bis[3-n-dodecylthio-2-(3-methyl-5-tert-octyl-4-hydroxyhydrocinnamoyloxy)propyl]-5,5-dimethylhydantoinand then vacuum dried. The resin is then extruded at 450°F (232.2°C)using a three-fourth inch (1.905 cm) extruder having a 24:1 L/D ratio.The melt flow rate of a sample of the resin is determined after eachextrusion according to ASTM test D-1238. Polyethylene stabilized withabove compound is found to undergo less change in the melt flow ratethan the unstabilized polyethylene.

EXAMPLE 13

A quantity of SBR emulsion containing 100 g of rubber (500 ml of a 20%SBR emulsion obtained commercially from Texas U.S. as Synpol 1500)previously stored under nitrogen, is placed in a beaker and stirredvigorously. The pH of the emulsion is adjusted to 10.5 with a 0.5N NaOHsolution.

To the emulsion is added 50 ml of 25% NaCl solution. A 6% NaCl solutionadjusted with hydrochloric acid to a pH 1.5 is added in a thin streamwith vigorous stirring. When pH 6.5 is reached, the rubber begins tocoagulate and the addition is slowed down in order to maintain uniformagitation. The addition of the acidic 6% NaCl solution is terminatedwhen a pH 3.5 is reached. The coagulated crumb-rubber slurry at pH 3.5is stirred for one-half hour.

The coagulated rubber is isolated by filtration through cheese cloth,and rinsed with distilled water. After three subsequent washings withfresh distilled water, the coagulated rubber is dried, first at 25 mm Hgand finally to constant weight under high vacuum (<1 mm) at 40° to 45°C.

The dried rubber (25 g) is heated under nitrogen at 125°C in a Brabendermixer and to this is added with mixing 0.1% by weight of2,2-bis[4-(3-cyclohexylthio-2-(3-methyl-5-tert-amyl-4-hydroxybenzoxy))propoxyphenyl]propane.

Portions of the rubber are oven aged at 100°C. At various intervals gelcontent is determined on the rubber. The rubber stabilized with theabove compound shows much less gel formation than the unstabilizedsample.

EXAMPLE 14

To 50 g of polyacetal resin containing 0.1% of an acid scavenger,dicyandiamide, is added 0.2% by weight of2,2-bis[4-(3-methylthio-2-(3,5-di-tert-octyl-4-hydroxyphenylacetoxy))propoxyphenyl]propane,and milled for 7 minutes at 200°C in a Brabender Plastirecorder. Themilled formulation is subsequently pressed into a 40 mil (1.016 mm)sheet at 215°C at 350 psi (24.5 Kg/cm²) for 90 seconds then cooledquickly in a cold press at 350 psi (24.5 Kg/cm²). The stabilized sheetsare then remolded for 2 minutes at contact pressure and for 3 minutes at300 psi (21 Kg/cm²) at 215°C to give plaques 1.5 inches × 1.5 inches ×125 mil (3.81 cm × 5.715 cm × 3.175 mm.). The plaques are aged in theoven at 60°C and the weight loss of the specimen is determinedperiodically until a 4% weight loss is reached. The stabilized sampletakes a much longer time to reach this 4% weight loss than does theunstabilized sample.

EXAMPLE 15

Unstabilized, thoroughly dried polyethylene terephthalate chips are dryblended with 1.0% by weight of2,2-bis[4-(3-n-octylthio-2-(6-(3,5-di-tert-butyl-4-hydroxyphenyl)caproyloxy))propoxyphenyl]propane.60/10 denier multifilament is melt spun at a melt temperature of 290°Cand cold oriented 3 to 1. The oriented fibers are wound into skeins andoven aged at 140°C. The stabilized material exhibits greater retentionof tensile strength after 24 hours than the unstabilized material.

EXAMPLE 16

A stabilized high temperature lubricating oil is prepared byincorporating 0.05% by weight of2,2-bis[4-(3-n-octadecylthio-2-(5-(3,5-di-tert-butyl-4-hydroxyphenyl)valeroyloxy))propoxyphenyl]propaneto the lubricant which comprises diisoamyl adipate. The stabilizedcomposition is compared with the unstabilized lubricant by heating at175°C in the presence of air and metallic catalysts according to thetest method described in Military Specification Mil-I-7808c. After 72hours, the blank containing no stabilizer contains more sludge and has agreater viscosity than the stabilized lubricant.

What is claimed is:
 1. A compound having the formula ##EQU6## wherein R₁is alkyl of 1 to 30 carbon atoms, cycloalkyl of 5 to 12 carbon atoms,alkylthioethyl of 4 to 27 atoms in the chain or alkylpolyoxyalkylene of4 to 27 atoms in the chain having the general structure R°(OC_(n)H_(2n))_(h) or R°(OCH₂ CHR')_(h) where R° is alkyl of 1 to 18 carbonatoms, n is 2 to 4, R' is hydrogen, methyl or ethyl and h is 1 to 3,R₂is the group ##SPC12## R₃ is hydrogen, alkyl of 1 to 8 carbon atoms,cycloalkyl of 5 to 6 carbon atoms or α-methylbenzyl, R₄ is alkyl of 1 to8 carbon atoms or cycloalkyl of 5 to 6 carbon atoms, R₅ is hydrogen orlower alkyl of 1 to 4 carbon atoms or R₃ and R₅ together are a butylenechain which, together with the phenyl ring, form a tetrahydronaphthylgroup, and provided when R₃ is hydrogen, R₅ is alkyl and R₄ is locatedon the carbon atom ortho to the hydroxyl group, A is a covalent carbonbond or a straight or branched lower alkylene having 1 to 8 carbonatoms, Q is the group ##SPC13## R₆ is hydrogen or alkyl of 1 to 4 carbonatoms, R₇ is hydrogen or alkyl of 1 to 8 carbon atoms, and Z is oxygenor sulfur.
 2. A compound according to claim 1 whereinR₁ is alkyl of 1 to18 carbon atoms, R₃ is hydrogen or alkyl of 1 to 4 carbon atoms, R₄ isbranched alkyl of 3 to 8 carbon atoms, R₅ is hydrogen or alkyl of 1 to 3carbon atoms, A is a straight chain alkylene of 1 to 3 carbon atoms, R₆is hydrogen or methyl, and R₇ is hydrogen or alkyl of 1 to 3 carbonatoms.
 3. A compound according to claim 1 whereinR₁ is alkyl of 8 to 18carbon atoms, R₃ is methyl or tert-butyl, R₄ is tert-butyl, R₅ ishydrogen or methyl, A is methylene or ethylene, R₆ is methyl, and R₇ ismethyl.
 4. The compound according to claim 1 which is2,2-bis[4-(3-n-dodecylthio-2-(3-methyl-5-tert-butyl-4-hydroxyhydrocinnamoyloxy))propoxyphenyl]propane.